Conceptual

Effective Hamiltonian Definitions of Work and Heat in Open Quantum Systems

In quantum thermodynamics the split of an open system's internal energy into work and heat has long been ambiguous. This concept resolves it by recognizing that a Hamiltonian plays two roles - fixing the internal energy as its expectation value and generating the dynamics - and decomposing it into a part that commutes with the density operator (which fixes the internal energy) and an orthogonal part that drives the evolution; applying the same decomposition to the system-environment interaction yields an effective Hamiltonian giving consistent, dynamics-dependent definitions of internal energy, work, and heat.